1. Technical Field
This application claims the benefit of Korean Patent Application No. 10-2014-0182351 filed on Dec. 17, 2014 and Korean Patent Application No. 10-2015-0154075 filed on Nov. 3, 2015, the content of each are incorporated herein by reference in its entirety.
The present invention relates to a method of separating and recovering 1,3-butadiene and methylethylketone from dehydration products of 2,3-butanediol. More particularly, the present invention relates to a method of efficiently separating 1,3-butadiene and methylethylketone, which are compounds of interest, from byproducts or impurities in the dehydration products of 2,3-butanediol so as to recover the compounds of interest at high purity.
2. Description of the Related Art
1,3-butadiene is used in various manufacturing sectors, including those of hydrocarbon fuels, polymers, synthetic rubber, plastics, and fibers, and methylethylketone is widely utilized as a solvent in the synthesis of various fine chemicals. However, these compounds, especially 1,3-butadiene, which is mainly prepared from petroleum-based energy sources (e.g. steam cracking), suffers from problems including limited resource availability, regional disparities, and environmental pollution. Furthermore, as more gas crackers using abundant gas resources are built, C4 oil fractions are reduced, and thus increased yield of 1,3-butadiene is required. Recently, the demand for 1,3-butadiene is drastically increasing because synthetic rubber is widely utilized in the manufacture of various electric products and vehicles and because of the rapid economic growth in China and the like. Also, the demand for methylethylketone is increasing in China in the fields of plastics, fibers, construction, furniture, vehicles, and electronics, and product costs are continuously increasing.
With the goal of solving the problems, thorough research is ongoing into the full or partial replacement of petroleum resources with biomass. In this regard, the preparation of 1,3-butadiene and methylethylketone through the dehydration of 2,3-butanediol is known. 2,3-butanediol is known to be produced through fermentation by microorganisms (e.g. Bacillus polymyxa or Klebsiella pneumonia).
The reaction mechanism for converting a polyhydroxy compound such as 2,3-butanediol into a diolefin such as 1,3-butadiene has been known since the 1930s (e.g. U.S. Pat. No. 1,841,055; Bourns A N, Nicholss R V V, The catalytic action of aluminium silicates. I. The dehydration of 2,3-butanediol and 2-butanone over activated Morden bentonite. Can J Research 25b:80-89 (1947)). Based on recent research results, 2,3-butanediol is converted into 1-buten-3-ol through dehydration and then additionally dehydrated, thereby producing 1,3-buradiene, and 2,3-butanediol is converted into 2,3-dimethyl oxirane through dehydration, whereby methylethylketone is produced.
For dehydration, a variety of catalysts, for example, a cesium oxide-silica composite (Korean Patent Application Publication No. 2012-0099818), a niobium-silicate-phosphate composite (Korean Patent Application Publication No. 2012-0079584), etc. are disclosed. In this regard, the use of a phosphate compound catalyst, such as hydroxyapatite and/or calcium pyrophosphate, to increase the selectivity and yield of 1,3-butadiene and/or methylethylketone, is known these days (Korean Patent No. 1287167).
In the conventional techniques, attention is paid to dehydration catalysts and/or reaction conditions for converting 2,3-butanediol into 1,3-butadiene and/or methylethylketone, but specific methods of efficiently recovering highly pure 1,3-butadiene and/or methylethylketone from the dehydration products have not been devised. Upon real-world operation, the dehydration products of 2,3-butanediol essentially include a variety of byproducts (especially by-oxygenates) and water, and thus the separation of the compounds of interest at high yield and high efficiency is required. Specifically, the dehydration products include a variety of oxygen-containing compounds (carbonyl compounds such as aldehyde, alcohol, etc.), water resulting from dehydration and the like, in addition to 1,3-butadiene and/or methylethylketone.
In this regard, the standards for 1,3-butadiene and methylethylketone in related fields are shown in Tables 1 and 2 below.
TABLE 1ItemsStandardTest methodConjugated diene, wt %Min. 99.0ASTM D 2593Peroxide, wt ppmMax. 10ASTM D 1022Acetylene, wt ppmMax. 400ASTM D 2593Carbonyl compound Max. 100ASTM D 4423(acetaldehyde), wt ppmButadiene dimer, wt %Max. 0.2ASTM D 2426Non-volatile, wt %Max. 0.1ASTM D 1025Total sulfur, wt ppmMax 10ASTM D 2784 or UOP 791
TABLE 2ItemsStandardTest methodColor (Pt—Co)Max. 10ASTM D4176Water, wt %Max. 0.05ASTM D1364Acidity (CH3COOH), mg/kgMax. 30ASTM D1613Methylethylketone (dry basis), wt %Min. 99.75—Alcohol impurities, wt %Max. 0.05—Ethylacetate, wt %Max. 0.15—Acetone, wt %Max. 0.1—
However, since various compounds produced via the dehydration reaction include compounds having similar boiling points, the separation efficiency thereof is low when typical distillation alone is conducted, undesirably resulting in low yield. Furthermore, it is difficult to satisfy the standards of highly pure 1,3-butadiene and methylethylketone.
For these reasons, processes of effectively separating 1,3-butadiene and methylethylketone as compounds of interest from various byproducts of the dehydration of 2,3-butanediol so as to recover the compounds of interest at high yield and high purity are not specifically known in the related art.